REVIEW Open Access

2020 update of the WSES guidelines for themanagement of acute colonic diverticulitisin the emergency settingMassimo Sartelli1* , Dieter G. Weber2, Yoram Kluger3, Luca Ansaloni4, Federico Coccolini5, Fikri Abu-Zidan6,Goran Augustin7, Offir Ben-Ishay3, Walter L. Biffl8, Konstantinos Bouliaris9, Rodolfo Catena10, Marco Ceresoli11,12,Osvaldo Chiara13, Massimo Chiarugi5, Raul Coimbra14, Francesco Cortese15, Yunfeng Cui16, Dimitris Damaskos17,Gian Luigi de’ Angelis18, Samir Delibegovic19, Zaza Demetrashvili20, Belinda De Simone21, Francesco Di Marzo22,Salomone Di Saverio23, Therese M. Duane24, Mario Paulo Faro25, Gustavo P. Fraga26, George Gkiokas27,Carlos Augusto Gomes28, Timothy C. Hardcastle29, Andreas Hecker30, Aleksandar Karamarkovic31, Jeffry Kashuk32,Vladimir Khokha33, Andrew W. Kirkpatrick34, Kenneth Y. Y. Kok35, Kenji Inaba36, Arda Isik37,Francesco M. Labricciosa38, Rifat Latifi39, Ari Leppäniemi40, Andrey Litvin41, John E. Mazuski42, Ronald V. Maier43,Sanjay Marwah44, Michael McFarlane45, Ernest E. Moore46, Frederick A. Moore47, Ionut Negoi48, Leonardo Pagani49,Kemal Rasa50, Ines Rubio-Perez51, Boris Sakakushev52, Norio Sato53, Gabriele Sganga54, Walter Siquini1,Antonio Tarasconi10, Matti Tolonen40, Jan Ulrych55, Sannop K. Zachariah56 and Fausto Catena10

Abstract

Acute colonic diverticulitis is one of the most common clinical conditions encountered by surgeons in the acutesetting. An international multidisciplinary panel of experts from the World Society of Emergency Surgery (WSES)updated its guidelines for management of acute left-sided colonic diverticulitis (ALCD) according to the mostrecent available literature. The update includes recent changes introduced in the management of ALCD. The newupdate has been further integrated with advances in acute right-sided colonic diverticulitis (ARCD) that is morecommon than ALCD in select regions of the world.

Keywords: Acute left-sided colonic diverticulitis, Acute right-sided colonic diverticulitis, Peritonitis, Abscess

IntroductionAcute left-sided colonic diverticulosis is common in West-ern countries with its prevalence increasing throughout theworld, which is likely due to changes in lifestyle [1]. Al-though left-sided colonic diverticulosis remains more com-mon among elderly patients, a dramatic rise of its incidencehas been seen in younger age groups in recent years [2]. Re-cent evidence suggests that lifetime risk of developing acute

left-sided colonic diverticulitis (ALCD) is about 4% amongpatients with diverticulosis [3], and data from Western pop-ulations suggest that up to one fifth of patients with acutediverticulitis are under 50 years of age [4–6].ALCD is a common problem encountered by Western

surgeons in the acute setting. The sigmoid colon is usu-ally the most commonly involved part, while acute right-sided diverticulitis (ARCD) is rarer but much more com-mon in non-Western populations.

© The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License,which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you giveappropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate ifchanges were made. The images or other third party material in this article are included in the article's Creative Commonslicence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commonslicence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtainpermission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to thedata made available in this article, unless otherwise stated in a credit line to the data.

* Correspondence: massimosartelli@gmail.com1Department of Surgery, Macerata Hospital, Macerata, ItalyFull list of author information is available at the end of the article

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 https://doi.org/10.1186/s13017-020-00313-4

MethodsThe World Society of Emergency Surgery (WSES) guide-lines for management of ALCD were published in 2016[7]. In 2020, the guidelines were revised and updated.The present guidelines have been developed according

to the GRADE methodology [8, 9]. The GRADE system isa hierarchical, evidence-based tool, which systematicallyevaluates the available literature and focuses on the levelof evidence based upon the types of studies included. Thequality of evidence can be marked as high, moderate, low,or very low. This could be either downgraded in case ofsignificant bias or upgraded when multiple high-qualitystudies showed consistent results. The highest quality ofevidence studies (systematic reviews with meta-analysis ofrandomized controlled trials) was assessed first. If themeta-analysis was of sufficient quality, it was used to an-swer the research question. If no meta-analysis of suffi-cient quality was found, randomized controlled trials(RCTs) and non-randomized cohort studies (n-RCS) wereevaluated. The strength of the recommendation was basedon the level of evidence and qualified as weak or strong.A multidisciplinary panel of experts, coordinated by a

central coordinator, was selected to serve as experts inthis 2020 update of the WSES guidelines for the man-agement of acute left-sided colonic diverticulitis (ALCD).The experts reviewed and updated the original list of keyquestions on the diagnosis and treatment of ALCD ad-dressed in the previous version of the guidelines.For each statement, a consensus among the panel of

experts was reached using a Delphi approach. State-ments were approved with an agreement of ≥ 80%.After the approval of the statements, the expert panel

met via email to prepare and revise the definitive guidelines.The manuscript was successively reviewed by all membersand ultimately revised as the present manuscript.

Which classification should be used in patientswith ALCD?There are multiple classification systems for ALCD. Nonehas been conclusively proven to be superior in predictingpatient outcomes, and therefore, a specific recommenda-tion cannot be provided.ALCD ranges in severity from uncomplicated phleg-

monous diverticulitis to complicated diverticulitis in-cluding abscess and/or perforation.For the past three decades, the Hinchey classification

has been the most used classification in the internationalliterature [10].In patients with surgical findings of abscesses and peri-

tonitis, Hinchey et al. classified the severity of acute di-verticulitis into four levels:

1 Pericolic abscess2 Pelvic, intra-abdominal, or retroperitoneal abscess

3 Generalized purulent peritonitis4 Generalized fecal peritonitis

In recent years, the management of ALCD has chan-ged dramatically.Computer tomography (CT) imaging has become a

primary diagnostic tool in the diagnosis and staging ofpatients with ALCD, and more detailed information pro-vided by CT scans led to several modifications of theHinchey classification [4, 11–15].In 1989, Neff et al. presented a new classification of ALCD

based on CT findings. It consisted of five stages, rangingfrom radiological diagnosis of uncomplicated (stage 0) topneumoperitoneum with abundant free liquid (stage 4) [11]:

0 Uncomplicated diverticulitis; diverticula, thickeningof the wall, increased density of the pericolic fat

1 Locally complicated with local abscess2 Complicated with pelvic abscess3 Complicated with distant abscess4 Complicated with other distant complications

In 2002, Ambrosetti et al. [12] classified ALCD into se-vere or moderate disease. In this classification, the CTscan determined the grade of severity guiding the phys-ician in the treatment of acute complications. Moderatediverticulitis was defined by wall thickening of ≥ 5 mmand signs of pericolic fat inflammation. Severe diverticu-litis was defined by wall thickening accompanied by ab-scess, extraluminal gas, or extraluminal contrast:

1. Moderate diverticulitis(a) Localized sigmoid wall thickening (≥ 5 mm)(b) Pericolic fat stranding

2. Severe diverticulitis(a) Abscess(b) Extraluminal gas(c) Extraluminal contrast

In 2005, Kaiser et al. [13] modified the Hinchey classi-fication according to specific CT findings:Stage 0: mild clinical diverticulitisStage 1a: confined pericolic inflammationStage 1b: confined pericolic abscessStage 2: pelvic or distant intra-abdominal abscessStage 3: generalized purulent peritonitisStage 4: fecal peritonitis at presentationIn 2013, Mora Lopez et al. proposed [14] a modifica-

tion of the previous Neff classification dividing Neffstage 1 into stage 1a (localized pneumoperitoneum inthe form of gas bubbles) and 1b (abscess < 4 cm).

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 2 of 18

0Uncomplicated diverticulitis. Diverticula, thickeningof the wall, increased density of the pericolic fat1Locally complicated diverticulitis1aLocalized pneumoperitoneum in the form of gas bubbles1bAbscess (< 4 cm)2Complicated diverticulitis with pelvic abscess. Ab-

scess > 4 cm in pelvis3Complicated diverticulitis with distant abscess. Ab-

scess in abdominal cavity (outside pelvis)4Complicated diverticulitis with other distant compli-

cations. Abundant pneumoperitoneum and/or intra-abdominal free liquidRecently, Sallinen et al. [15] published an interesting

retrospective study of patients treated for ALCD, settingthe stage for the treatment of acute diverticulitis basedon clinical, radiologic, and physiologic parameters:1Uncomplicated diverticulitis2Complicated diverticulitis with small abscess (< 6 cm)3Complicated diverticulitis with large abscess (≥ 6 cm)

or distant intraperitoneal or retroperitoneal gas4Generalized peritonitis without organ dysfunction5Generalized peritonitis with organ dysfunctionFinally, a proposal for a CT-guided classification of

ALCD was published in 2015 by the WSES acute diver-ticulitis working group [7].It is a simple classification system of ALCD based on CT

scan findings. It may guide clinicians in the management ofacute diverticulitis and may be universally accepted for dayto day practice. The WSES classification divides acute di-verticulitis into 2 groups: uncomplicated and complicated.In the event of uncomplicated acute diverticulitis, the

infection only involves the colon and does not extend tothe peritoneum. In the event of complicated acute diver-ticulitis, the infectious process proceeds beyond the colon.Complicated acute diverticulitis is divided into 4 stages,based on the extension of the infectious process:Uncomplicated0Diverticula, thickening of the wall, increased density

of the pericolic fatComplicated1APericolic air bubbles or small amount of pericolic

fluid without abscess (within 5 cm from inflammedbowel segment)1BAbscess ≤ 4 cm2AAbscess > 4 cm2BDistant gas (> 5 cm from inflammed bowel segment)3Diffuse fluid without distant free gas4Diffuse fluid with distant free gas

What is the best way to make a diagnosis ofALCD?In patients with suspected ALCD, we suggest a complete as-sessment of the patients using clinical history, signs, labora-torial inflammation markers, and radiological findings

(weak recommendation based on very low-quality evidence,2D).In patients with suspected, ALCD we suggest against

diagnosis based only on clinical examination (weak rec-ommendation based on very low-quality evidence, 2D).Clinical findings of patients having ALCD include

acute pain or tenderness in the left lower quadrant thatmay be associated with increased inflammatory markers,including C-reactive protein (CRP) and white blood cellcount (WBC). Clinical diagnosis of ALCD usually lacksaccuracy. In a prospective analysis [16] conducted on802 consecutive patients who presented with abdominalpain to the emergency department, positive and negativepredictive values of clinical diagnosis were 0.65 and 0.98,respectively. Additional cross-sectional imaging had apositive and negative predictive value of 0.95 and 0.99,respectively. Additional radiology examinations im-proved the diagnostic accuracy in 37% of the patients,but changed the management in only 7%.In 2010, using logistic regression analysis, Laméris

et al. [17] developed a clinical decision rule for diagnosisof ALCD, based on 3 criteria: (1) direct tenderness onlyin the left lower quadrant, (2) CRP > 50mg/l, and (3) ab-sence of vomiting. Of 126 clinically suspected patientsenrolled in this prospective study, 30 patients had all 3features (24%), of whom 29 had a final diagnosis of acutediverticulitis (97%; 95% CI 83–99%). Of the 96 patientswithout all 3 features, 45 (47%) did not have diverticu-litis. In a quarter of patients with suspected diverticulitis,the diagnosis could be made clinically based on the com-bination of the three criteria.Andeweg et al. in 2011 [18], using retrospective data

from 287 patients, developed a clinical scoring systemfor the diagnosis of ALCD with diagnostic accuracy of86%. It was based on independent predictors of ALCDincluding age, a clinical history of one or more previousepisodes, localization of symptoms in the lower left ab-domen, aggravation of pain on movement, the absenceof vomiting, localization of abdominal tenderness onexamination in the lower left abdomen, and C-reactiveprotein of 50 mg/l or higher.CRP has been identified as a useful biomarker of in-

flammation, and it may be useful in the prediction of theclinical severity of acute diverticulitis as demonstratedby several recent studies [19–21]. To investigate thevalue of CRP and of other laboratory parameters of thepatients in the prediction of the clinical severity of acutediverticulitis, a retrospective study was published in2014 [19]. A CRP cutoff value of 170 mg/l significantlydiscriminated severe from mild diverticulitis (87.5% sen-sitivity, 91.1% specificity, area under the curve 0.942, p <0.00001). The authors concluded that CRP is a usefultool in the prediction of the clinical severity of acute di-verticulitis. A mild episode is very likely in patients with

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 3 of 18

CRP less than 170 mg/l. Those with higher CRP valueshave a greater probability of undergoing surgery or per-cutaneous drainage.In another study, the diagnostic value of serological in-

fection markers and body temperature, in discriminatingcomplicated from uncomplicated diverticulitis, wasassessed [20]. A total of 426 patients were included inthis study of which 364 (85%) presented with uncompli-cated and 62 (15%) with complicated diverticulitis. OnlyCRP was of sufficient diagnostic value (area under thecurve 0.715). The median CRP in patients with compli-cated diverticulitis was significantly higher than in pa-tients with uncomplicated disease (224 mg/l, range 99–284, vs. 87 mg/l, range 48–151, respectively). Patientswith a CRP of 25 mg/l had a 15% chance of having com-plicated diverticulitis. This increased from 23% at a CRPvalue of 100 mg/l to 47% for 250 mg/l or higher. The op-timal threshold was reached at 175 mg/l with a positivepredictive value of 36%, negative predictive value of 92%,sensitivity of 61%, and specificity of 82%.Mäkelä et al. [21] published a study comparing the

CRP values of 350 patients who presented for the firsttime with symptoms of acute diverticulitis with the CTfindings and clinical parameters by means of both uni-variate and multivariate analyses. CRP cutoff value of149.5 mg/l significantly discriminated acute uncompli-cated diverticulitis from complicated diverticulitis (speci-ficity 65%, sensitivity 85%, area under the curve 0.811, p= 0.0001). In multivariate analysis, a CRP value over 150mg/l and old age were independent risk factors for acutecomplicated diverticulitis. The mean CRP value was sig-nificantly higher in the patients who died (mean CRP of207 mg/l) than in those who survived (mean CRP of 139mg/l). In addition, a CRP value over 150 mg/l and freeabdominal fluid in CT were independent variables pre-dicting postoperative mortality. The study confirmedthat CRP is useful for predicting the severity of acute di-verticulitis on admission. The authors concluded thatpatients with a CRP value higher than 150 mg/l have anincreased risk of complicated diverticulitis and shouldalways undergo a CT examination.In 2018, a prospective study of patients with ALCD

was published [22]. All patients underwent CT. Indexparameters obtained at the initial evaluation in theemergency unit were analyzed to assess the associationwith the outcome. Ninety-nine patients were analyzed.Eighty-eight had mild radiological grading (Hinchey Ia/Ib), and 11 had severe radiological grading (Hinchey >Ib) (median index CRP 80 mg/l vs. 236 mg/l, p < 0.001).The median CRP level for Hinchey III/IV was 258.5 mg/l(201–297 mg/l). WBC, neutrophils/lymphocytes, serumcreatinine, serum glucose, generalized peritonitis, gener-alized abdominal tenderness, urinary symptoms, andindex CRP were related to severe disease. Index CRP

was the only independent predictor for Hinchey > Ib (p= 0.038). The optimal cutoff value calculated by receiveroperating characteristic curve analysis was found to be173 mg/l (sensitivity 90.9%, specificity 90.9%, p < 0.001).All patients who underwent radiologic-guided percutan-eous or surgery had an index CRP > 173mg/l andHinchey > Ib. However, the authors concluded that CRPshould not be used as a predictor of severity if there areconcomitant conditions that may affect its baselinelevels.The expert panel states that in very acutely onset dis-

ease, CRP values might not have rised yet, since there isa delay of 6–8 h from the onset of the disease, reachingpeak at 48 h. Therefore, caution should be used in usinglow CRP as excluding out acute diverticulitis [23].

What is the best imaging technique in patientswith suspected ALCD? What is the role ofultrasound (US) in patients with ALCD?In patients with suspected ALCD, we suggest contrast-enhanced CT scan of the abdomen as the imaging tech-nique of first choice (weak recommendation based onmoderate-quality evidence, 2B).We suggest to use US in the initial evaluation of pa-

tients with suspected ALCD where it is performed by anexpert operator. It has wide availability and easy accessi-bility. A step-up approach with CT performed after aninconclusive or negative US may be a safe approach forpatients suspected of acute diverticulitis (weak recom-mendation based on moderate-quality evidence, 2B).Radiological imaging techniques that are used for diag-

nosing ALCD in the emergency setting are US and CT.Currently, CT is the established method of choice whencompared to US and most guidelines cite the high ac-curacy and other advantages of CT. This approach is thegold standard for both the diagnosis and the staging ofpatients with ALCD due to its excellent sensitivity andspecificity [24–26]. CT scan can also rule out other diag-noses such as ovarian pathology, or leaking aortic or iliacaneurysm.CT findings in patients with ALCD may include diver-

ticulosis with associated colon wall thickening, fat strand-ing, phlegmon, extraluminal gas, abscess formation, orintra-abdominal free fluid. CT imaging can go beyond ac-curate diagnosis of ALCD. CT criteria may also be used todetermine the grade of severity and may drive treatmentplanning of patients [27]. US is a real-time dynamic exam-ination with wide availability and easy accessibility [28]. Itslimitations include operator dependency, poor assessmentin obese patients, and difficulty in the detection of free gasand deeply located abscesses [29].A systematic review and meta-analysis of studies [30]

that reported diagnostic accuracy of the clinical diagno-sis and diagnostic modalities in patients with suspected

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 4 of 18

diverticulitis was published in 2014. Summary sensitivityestimates for US were 90% (95% CI 76–98%) versus 95%(95% CI 91–97%) for CT (p = 0.86). Summary specificityestimates for US were 90% (95% CI 86–94%) versus 96%(95% CI 90–100%) for CT (p = 0.04).Although CT is the most sensitive imaging investiga-

tion for patients with suspected acute diverticulitis, astep-up approach with CT performed after an inconclu-sive or negative US has been proposed as safe and alter-native approach for patients with suspected acutediverticulitis [30, 31].Magnetic resonance imaging, which is not constrained

by the operator dependency limitation of compared toUS [32, 33], until now is currently difficult to perform atin the emergency department.

Are immunocompromised patients with ALCD atrisk for failure of standard, non-operativetreatment?We suggest that immunocompromised patients withALCD be considered at high risk for failure of standard,non-operative treatment (weak recommendation basedon very low-quality evidence, 2D).Immunocompromised patients are at increased risk

for complicated ALCD [34–37]. Immunocompromisedpatients may fail standard, non-operative treatment. Assuch, most of these patients require urgent surgicalintervention, and this is associated with a significantlyhigher mortality rate [38].A recent study by Biondo et al. [39] analyzed the rela-

tionship between the different causes of immunosuppres-sion (IMS) and ALCD. Immunocompromised patientswere divided in 5 groups according to the causes of IMS:group I, chronic corticosteroid therapy; group II, trans-plant patients; group III, malignant neoplasm disease;group IV, chronic renal failure; and group V, other im-munosuppressant treatments. The rate of emergency sur-gery was high (39.3%), and it was needed more frequentlyin group I (chronic corticosteroid therapy). In this study,postoperative mortality was of 31.6% and recurrence rateafter successful non-operative management occurred in30 patients (27.8%).

Should antibiotics be recommended inimmunocompetent patients with uncomplicatedacute diverticulitis?In immunocompetent patients with uncomplicated diver-ticulitis without signs of systemic inflammation, we rec-ommend to not prescribe antibiotic therapy (strongrecommendation based on high-quality evidence, 1A).In patients requiring antibiotic therapy, we recommend

oral administration whenever possible, primarily, be-cause an early switch from intravenous to oral therapymay facilitate a shorter inpatient length of stay (strong

recommendation based on moderate-quality evidence,1B).The definition of uncomplicated acute diverticulitis is

often vague and poorly defined. Uncomplicated acute di-verticulitis is defined as localized diverticular inflamma-tion without any abscess or perforation. A universallyaccepted classification divides intra-abdominal infections(IAIs) into complicated and uncomplicated [40]. In un-complicated IAIs, the infection only involves a singleorgan and does not extend to the peritoneum, while incomplicated IAIs, the infectious process extends beyondthe organ, causing either localized or diffuse peritonitis[40]. For a better definition of acute diverticulitis inthese guidelines, we use the term complicated and un-complicated according to the classification of IAIs.Uncomplicated acute diverticulitis is an anatomically

confined inflammatory process. CT findings include di-verticula, thickening of the wall, and increased density ofthe pericolic fat. Patients with uncomplicated diverticu-litis usually have an indolent course with a low incidenceof subsequent complications.The utility of antibiotics in acute uncomplicated acute

diverticulitis has been a point of controversy. In recentyears, several studies demonstrated that antimicrobialtreatment was not superior to withholding antibiotictherapy, in terms of clinical resolution, in patients withmild unperforated diverticulitis [41]. The current con-sensus is that uncomplicated acute diverticulitis may bea self-limiting condition in which local host defenses canmanage the inflammation without antibiotics in im-munocompetent patients. In this context, antibiotics arenot necessary in the treatment of uncomplicated disease.A multicenter randomized trial was published in 2012

by Chabok et al. involving ten surgical departments inSweden and one in Iceland recruiting 623 patients withcomputed tomography-confirmed acute uncomplicatedleft-sided diverticulitis [42]. Patients were randomized totreatment with (314 patients) or without (309 patients) an-tibiotics. Antibiotic treatment for acute uncomplicated di-verticulitis neither accelerated recovery nor preventedcomplications or recurrence. Therefore, antibiotics shouldbe reserved for the treatment of complicated diverticulitis.A prospective, single-arm, study overviewed [43] the

safety and efficacy of symptomatic (non-antibiotic) treat-ment for CT-proven uncomplicated acute diverticulitisduring a 30-day follow-up period. Overall, 161 patientswere included in the study, and 153 (95%) completedthe 30-day follow-up. A total of 14 (9%) patients hadpericolic gas. Altogether, 140 (87%) patients were treatedas outpatients, and 4 (3%) of them were admitted to thehospital during the follow-up. The primary outcomemeasure of the study was to find the incidence of com-plicated diverticulitis. None of the patients developedcomplicated diverticulitis or required surgery, but 2 days

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 5 of 18

(median) after inclusion, antibiotics were given to 14(9%, 6 orally, 8 intravenously) patients. A recent Dutchrandomized controlled trail of observational versus sys-temic antibiotic treatment (DIABOLO trial) [43] for afirst episode of CT-proven ALCD Hinchey stages 1a and1b confirmed that observational treatment without anti-biotics did not prolong recovery and could be consideredappropriate in these patients.This study included 22 clinical sites involving 528 pa-

tients; Hinchey modified stages 1a (confined pericolic in-flammation or phlegmon) to 1b (pericolic or mesocolicabscess) and Ambrosetti’s “mild/moderate” diverticulitisstage confirmed within 24 h by CT were included. Pa-tients with previous diverticulitis, higher Hinchey stages,or “severe” diverticulitis on Ambrosetti’s classificationwere excluded. The antibiotic treatment was a 10-daycourse of IV amoxicillin-clavulanic acid, 1200mg fourtimes daily for at least 48 h. After 48 h, the administra-tion route could be switched to per os, 625 mg threetimes daily. For observational treatment, patients had tomeet the criteria of tolerating a normal diet, temperatureless than 100.4 °F, a pain score below 4 on a visualanalogue scale (using only acetaminophen for pain con-trol), and the ability to support self at the same level asbefore illness. If the patient deteriorated, CT was re-peated and antibiotic treatment was started if thetemperature rose above 102.2 °F, blood cultures werepositive, or the patient was septic.No significant differences between the observation and

antibiotic treatment groups were found for secondaryendpoints: complicated diverticulitis (3.8% vs. 2.6%, re-spectively; p = 0.377), ongoing diverticulitis (7.3% vs.4.1%, respectively; p = 0.183), recurrent diverticulitis(3.4% vs. 3.0%, respectively; p = 0.494), sigmoid resection(3.8% vs. 2.3%, respectively; p = 0.323), readmission(17.6% vs. 12.0%, respectively; p = 0.148), adverse events(48.5% vs. 54.5%, respectively; p = 0.221), and mortality(1.1% vs. 0.4%, respectively; p = 0.432). Hospital stay wassignificantly shorter in the observation group (2 vs. 3days; p = 0.006). However, even if no significant differ-ences between Hinchey stages 1a and 1b diverticulitiswere found, the vast majority of patients included had adiagnosis of Hinchey stage 1a ALCD (90.1% in the ob-servational and 94% in the antibiotic-treated group) withonly a small percentage of patients with Hinchey stage 1stage 1b diverticulitis. Based on these results, the au-thors concluded that antibiotics can be safely omittedin patients with a first episode of uncomplicated(Hinchey 1a) ALCD. Similar results were found forHinchey 1b diverticulitis. However, since the triallacked power to detect smaller subgroup effects andthere are no other reports in literature, the authorsconcluded that observational treatment should be lim-ited to Hinchey 1a cases [44].

More recently, the long-term effects of omitting anti-biotics in uncomplicated ALCD were assessed after 24months’ follow-up of the DIABOLO trial [44]. Completecase analyses showed no difference in rates of recurrentdiverticulitis (15.4% in the observational group vs. 14.9%in the antibiotic group; p = 0.885), complicated diver-ticulitis (4.8% vs. 3.3%; p = 0.403), and sigmoid resection(9.0% vs. 5.0%; p = 0.085). Young patients (< 50 years)and patients with a pain score at presentation of 8 orhigher on a visual analogue pain scale were at risk forcomplicated or recurrent diverticulitis. In this multivari-able analysis, treatment type (with or without antibiotics)was not an independent predictor for complicated or re-current diverticulitis [45].Although the above studies have shown there is lim-

ited evidence that antibiotics should be routinely admin-istered to patients with uncomplicated diverticulitis, it isunderstood that disease severity varies in uncomplicateddiverticulitis and that further studies are needed to bet-ter risk-stratify these patients in order to determine theappropriate treatment course.The high mortality associated with sepsis requires cli-

nicians to maintain a high index of clinical suspicion, inthe conditions that predispose to sepsis in high-risk pa-tients [46]. The expert panel suggests antibiotic therapycovering Gram-negative bacilli and anaerobes in patientswith radiological documented uncomplicated acute di-verticulitis associated with systemic manifestations of in-fection or in high-risk patients such asimmunocompromised patients, elderly patients, andthose with comorbidities.If antibiotic therapy is necessary, oral administration

of antibiotics may be equally as effective as intravenousadministration. An expeditious switch from intravenousto oral may allow a rapid patient discharge.A randomized controlled trial (RCT) of oral versus

intravenous therapy for clinically diagnosed acute un-complicated diverticulitis was published in 2009 [47].Oral and intravenous regimens utilizing ciprofloxacinand metronidazole were compared. There were 41 pa-tients in the oral arm and 38 in the IV arm (n = 79). Nopatients had to be converted to intravenous antibioticsfrom the oral group. There was a complete resolution ofsymptoms in both groups. No studies have examined thevalue of dietary restriction or bed rest [48].

Could patients with uncomplicated ALCD betreated as outpatient?We suggest management in an outpatient setting for pa-tients with uncomplicated ALCD and no comorbidities.We suggest re-evaluation within 7 days. If the clinicalcondition deteriorates, re-evaluation should be carriedout earlier (weak recommendation based on moderate-quality evidence, 2B).

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 6 of 18

Patients with uncomplicated acute diverticulitis symp-toms without significant comorbidities, who are able totake fluids orally and manage themselves at home, canbe treated as outpatients. They should be re-evaluatedwithin 7 days from the time of the diagnosis. However, ifthe clinical condition deteriorates, re-evaluation shouldbe carried out earlier. Patients with significant comor-bidities and unable to take fluids orally should be treatedin hospital with intravenous fluids.Etzioni et al. [49] in 2010 published a retrospective

analysis, demonstrating that outpatient treatment was ef-fective for the vast majority (94%) of patients sufferingfrom acute diverticulitis. A systematic review on out-patient management of acute uncomplicated acute diver-ticulitis was recently published [50]. Jackson et al.concluded that current evidence suggested that a moreprogressive, ambulatory-based approach to the majorityof cases of acute uncomplicated acute diverticulitis wasjustified. Rodríguez-Cerrillo et al. [51] have recentlyshown that also elderly patients with comorbidities canbe safely treated at home avoiding hospital admission.The DIVER trial [52] has demonstrated that outpatient

treatment may be safe and effective in selected patientswith uncomplicated acute diverticulitis and can reducethe costs without negatively influencing the quality oflife of these patients. This multicenter, RCT included pa-tients older than 18 years with acute uncomplicated di-verticulitis. All the patients underwent abdominal CT.The first dose of antibiotic was given intravenously to allpatients in the emergency department, and then, patientswere either admitted to hospital or discharged. Among atotal of 132 patients, four patients in those admitted tohospital and three patients in those discharged to homemanagement developed treatment failure (there were nodifferences between the groups (p = 0.62)). The overallhealth care cost per episode was 3 times less in the out-patient treated group, with significant costs savings of€1124.70 per patient. No differences were observed be-tween the groups in terms of quality of life.A systematic review including 21 studies (11 prospect-

ive, 9 retrospective, and only 1 randomized trial) with1781 patients who had outpatient management of ALCDwas recently published [53]. The meta-analysis con-cluded that outpatient management is safe, and the over-all failure rate in an outpatient setting was 4.3% (95% CI2.6–6.3%). Location of diverticulitis is not a selection cri-terion for an outpatient strategy (p = 0.512). The othersubgroup analyses did not report any factors that influ-ence the rate of failure: previous episodes of acute diver-ticulitis (p = 0.163), comorbidities (p = 0.187), pericolicgas (p = 0.653), intra-abdominal abscess (p = 0.326),treatment according to a registered protocol (p = 0.078),type of follow-up (p = 0.700), type of antibiotic treat-ment (p = 0.647), or diabetes (p = 0.610). In patients

who failed outpatient treatment, the majority had pro-longed antibiotic therapy and only few had percutaneousdrainage for an abscess (0.13%) or surgical interventionfor perforation (0.06%). However, these results should beinterpreted with some caution because of the low qualityof available data. The data reported suggested that out-patient management is safe if associated with an accur-ate selection of patients (40%); no subgroup analysisdemonstrated significant differences between groups (in-cluding comorbidities, previous episode and diabetes).The main limitations of the findings of the present re-view concern their applicability in common clinical prac-tice as it was impossible to identify strict criteria offailure.Another review about outpatient management of

ALCD was published in 2017 [54]. The search yielded192 publications. Of these, 10 studies met the inclusioncriteria including 1 RCT, 6 clinical controlled trials, and3 case series. There was no difference in failure rates ofmedical treatment (6.5 vs. 4.6%, p = 0.32) or in recur-rence rates (13.0 vs. 12.1%, p = 0.81) between those re-ceiving ambulatory care and inpatient care foruncomplicated diverticulitis. Ambulatory treatment wasassociated with an estimated daily cost savings of be-tween €600 and €1,900 per patient treated. Meta-analysis of data was not possible due to heterogeneity instudy designs and inclusion criteria.

What is the best treatment for patients with acutediverticulitis with CT findings of pericolic gas?In patients with CT findings of pericolic extraluminalgas, we suggest a trial of non-operative treatment withantibiotic therapy (weak recommendation based on low-quality evidence, 2C).High mortality associated with sepsis requires main-

taining a high index of clinical suspicion for deterior-ation and more aggressive management. WSES expertpanel recommends antibiotic therapy in patients withpericolic extraluminal gas [27]. A sub-analysis of the DIA-BOLO trial was recently published [55]. All patients withHinchey 1a diverticulitis and with isolated pericolic gas onCT were identified. Pericolic gas was defined as gas lo-cated < 5 cm from the affected segment of colon. The pri-mary outcome of the study was failure of non-operativemanagement that was defined as need for percutaneousabscess drainage or emergency surgery within 30 daysafter presentation. A multivariate logistic regression ana-lyses of clinical, radiological, and laboratorial parameterswith respect to treatment failure was performed. A total of109 patients were included. Fifty-two (48%) patients weretreated with antibiotics. Nine (8%) patients failed non-operative management, seven (13%) in the antibiotic treat-ment group and two (4%) in the non-antibiotic group (p =0.083). Only increased CRP level at presentation was an

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 7 of 18

independent predictor for treatment failure. The authorsconcluded that non-operative treatment in diverticulitispatients with isolated pericolic gas is a suitable treatmentstrategy. However, due to the low event rate, it remainsuncertain whether antibiotic treatment is necessary in pa-tients with isolated pericolic gas.

What is the best treatment for patients with asmall diverticular abscess (< 4–5 cm)? What is thebest treatment for patients with large diverticularabscess?For patients with a small (< 4–5 cm) diverticular abscess,we suggest an initial trial of non-operative treatmentwith antibiotics alone (weak recommendation based onlow-quality evidence, 2C).We suggest to treat patients with large abscesses with

percutaneous drainage combined with antibiotic treat-ment; whenever percutaneous drainage of the abscess isnot feasible or not available, we suggest to initially treatpatients with large abscesses with antibiotic therapyalone, clinical conditions permitting. Alternatively, anoperative intervention is required (weak recommendationbased on low-quality evidence, 2C).Approximately 15–20% of patients admitted with

acute diverticulitis have an abscess on CT scan [56]. Thetreatment of abscess always requires antibiotic therapy.If the abscess is limited in size, systemic antibiotic ther-apy alone is considered safe and effective in removingthe abscess and solving acute inflammation with apooled failure rate of 20% and a mortality rate of 0.6%[57].When abscess diameter is larger, antibiotics could fail

to reach the adequate concentration inside the abscessleading to an increased failure rate.The size of 4–5 cm may be a reasonable limit between

antibiotic treatment alone, versus percutaneous drainagecombined with antibiotic treatment in the managementof diverticular abscesses [58–62]. When the patient’sclinical conditions allow it and percutaneous drainage isnot feasible, antibiotic therapy alone can be considered.However, careful clinical monitoring is mandatory. A highsuspicion for surgical control of the septic source shouldbe maintained and a surgical treatment should be per-formed if the patient shows a worsening of inflammatorysigns or the abscess does not reduce with medical therapy.There are currently no randomized studies available on

the best treatment of intra-abdominal abscess from acutediverticulitis, and current recommendations are basedonly on observational studies. A retrospective study com-paring outcomes of selected patients treated with initialantibiotics alone versus percutaneous drainage was pub-lished in 2015 by Elagili et al. [63]. All patients with diver-ticular abscess ≥ 3 cm in diameter treated in a singleinstitution in 1994–2012 with percutaneous drainage or

antibiotics alone followed by surgery were identified froman institutional diverticular disease database. Groups werecompared based on patient and disease characteristics,treatment failures, and postoperative outcomes. Thirty-two patients were treated with antibiotics alone because ofeither technically impossible percutaneous drainage orsurgeon preference, while 114 underwent percutaneousdrainage. Urgent surgery was required in 8 patients withpersistent symptoms during treatment with antibioticsalone (25%) and in 21 patients (18%) after initial percu-taneous drainage (p = 0.21). Patients treated with antibi-otics had a significantly smaller abscess diameter (5.9 vs.7.1 cm, p = 0.001) and shorter interval from initial treat-ment to sigmoidectomy (mean 50 vs. 80 days, p = 0.02).Postoperative complications following antibiotics alonewere significantly less severe than after percutaneousdrainage based on the Clavien-Dindo classification (p =0.04).In patients displaying an appropriate clinical improve-

ment, the drainage catheter can be removed when theoutput has ceased or decreased substantially. In doubtfulcases, a CT scan can be performed with water-solublecontrast via the percutaneous drainage catheter prior todrain removal. If no identifiable cavity remains, the cath-eter should be removed. If resolution of the abscess isnot reached and the patient has no clinical improve-ment, further drainage or catheter repositioning mightbe indicated and may eventually necessitate surgery.

Should an early colonic evaluation be planned inpatients treated non-operatively for a diverticularabscess? Should an early colonic evaluation berecommended for patients with a CT-proveduncomplicated acute diverticulitis treated non-operatively?In patients with diverticular abscesses treated non-operatively, we suggest to plan an early colonic evalu-ation (4–6 weeks) (weak recommendation based on low-quality evidence, 2C).In patients with CT-proven uncomplicated diverticu-

litis treated non-operatively, we do not recommend rou-tine colonic evaluation (weak recommendation based onmoderate-quality evidence, 2B).Colonic localized abscess is an uncommon, but pos-

sible, presentation of an occult colon malignancy, and itmay mimic complicated diverticular disease [64, 65]. Ithas been demonstrated that the risk of malignancy aftera CT-proven uncomplicated diverticulitis is low and, inthe absence of other indications, routine colonoscopymay not be necessary. A systematic review investigatingthe rate of colorectal cancer (CRC) found by colonos-copy after an episode of uncomplicated diverticulitis waspublished in 2014 [66]. Nine studies met the inclusioncriteria and included a total number of 2490 patients

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 8 of 18

with uncomplicated diverticulitis. Subsequent colonos-copy after an episode of uncomplicated diverticulitis wasperformed in 1468 patients (59%). Seventeen patientswere diagnosed with CRC, having a prevalence of 1.16%(95% confidence interval 0.72–1.9% for CRC). Hyper-plastic polyps were seen in 156 patients (10.6%), low-grade adenoma in 90 patients (6.1%), and advanced ad-enoma in 32 patients (2.2%). The results of this reviewdemonstrate that unless colonoscopy is regarded forscreening in individuals aged 50 years and older, routinecolonoscopy in the absence of other clinical signs ofCRC is not required in patients following an episode ofacute uncomplicated diverticulitis.Another systematic review and meta-analysis on the

role of routine colonic evaluation after radiologicallyconfirmed acute diverticulitis was published in 2014[67]. Eleven studies from 7 countries were included inthe analysis. Among 1970 patients, cancer was onlyfound in 22 (0.01%) cases. The risk of malignancy after aradiologically proven episode of acute uncomplicated di-verticulitis was low. Patients with complicated diverticu-litis had a significant risk of CRC at subsequent colonicevaluation.A retrospective study of 633 patients with acute diver-

ticulitis diagnosed by CT was published in 2014 [68]. Ofthe 663 patients, 97 patients underwent emergency re-section, while 536 patients were treated non-operatively,394 of whom subsequently underwent colonoscopy. Thefindings showed 17 cancers (2.7%) in patients with aninitial diagnosis of acute diverticulitis. As shown by CT,16 cancer patients (94%) had an abscess, while one pa-tient had pericolic extraluminal gas but no abscess. Ofthe patients with an abscess, 11.4% had cancer mimick-ing acute diverticulitis. No cancer was found in the pa-tients with uncomplicated diverticulitis.

What is the role of non-operative treatment inpatients with CT findings of distant gas withoutdiffuse intra-abdominal fluid?In patients with CT findings of distant free gas withoutdiffuse intra-abdominal fluid, we suggest a non-operativetreatment in selected patients only if a close follow-upcan be performed (weak recommendation based on verylow-quality evidence, 2D).Although most patients hospitalized for acute diver-

ticulitis can be managed by non-operative treatment, upto 25% may require urgent operative intervention [69].Patients with diffuse peritonitis are typically critically illpatients and require prompt fluid resuscitation, anti-biotic administration, and surgery. While the absoluteprevalence of perforated diverticulitis complicated bygeneralized peritonitis is low, it is associated with signifi-cant postoperative mortality, regardless of selected surgi-cal strategy.

Despite CT findings of distant free gas (a known pre-dictor of failure of non-operative treatment [27]), Dhar-marajan et al. [70] described a high success rate for non-operative management in patients with acute diverticu-litis and a pneumoperitoneum, excluding those withhemodynamic instability. Sallinen et al. [71] reported re-sults of non-operative management in patients with CTverified extraluminal gas. The study showed that non-operative treatment was feasible therapy only forhemodynamically stable patients with pericolic extra-luminal gas or with small amount of distant intraperito-neal gas in the absence of clinical diffuse peritonitis orfluid in the fossa Douglas. Occurrence of large amountof distant intraperitoneal gas or distant retroperitonealgas even in the absence of clinical generalized peritonitiswas associated with high failure rate (57–60%) of non-operative management. Moreover, nearly 60% patientswith distant intraperitoneal gas were primarily treated bysurgery.Highly selected group of patients at this stage may be

treated by conservative treatment. However, it may beassociated with a significant failure rate and a carefulclinical and CT monitoring is mandatory [20]. Suggestedintervention for patients at this stage should be surgicalresection and anastomosis with or without stoma instable patients without comorbidities, and Hartmann’sprocedure (HP) in unstable patients or in patients withmultiple comorbidities [27].

Should laparoscopic lavage and drainage berecommended in patients with diffuse peritonitisdue to diverticular perforation?We suggest performing laparoscopic peritoneal lavageand drainage only in very selected patients with general-ized peritonitis. It is not considered as the first line treat-ment in patients with peritonitis from acute colonicdiverticulitis (weak recommendation based on high-quality evidence, 2A).A minimally invasive approach using laparoscopic

peritoneal lavage and drainage has been debated in re-cent years as an alternative to colonic resection [72]. Itcan potentially avoid a stoma in patients with diffuseperitonitis. It consists of the laparoscopic aspiration ofpus followed by abdominal lavage and the placement ofabdominal drains, which remain for many days after theprocedure. In 2013, a Dutch retrospective analysis of 38patients [73] treated by laparoscopic lavage was pub-lished highlighting some doubts about this procedure totreat critically ill patients. In seven patients, this ap-proach did not control abdominal sepsis, two patientsdied of multiple organ failure and five ones required fur-ther surgical interventions (three Hartmann resection,one diverting stoma, and one perforation closure). Oneof these died from aspiration, and the remaining four

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 9 of 18

experienced prolonged and complicated hospital stay.Multiple comorbidities, IMS, a high CRP level, and/or ahigh Mannheim Peritonitis Index were also predictors ofa high risk of failure. The authors concluded that patientselection was of utmost importance and identification ofan overt sigmoid perforation is of critical importance.Great debate is still open on this topic, mainly due tothe discrepancy and sometime disappointing results ofthe latest prospective trials such as SCANDIV, Ladies,and DILALA trials [74–76]In 2014, the first results from the RCT DILALA were

published [74]. Initial diagnostic laparoscopy showingHinchey III disease was followed by randomization be-tween laparoscopic lavage and colon resection andstoma. Morbidity and mortality after laparoscopic lavagedid not differ when compared with the Hartmann pro-cedure. Laparoscopic lavage resulted in shorter operatingtime, shorter time in the recovery unit, and shorter hos-pital stay with the avoidance of a stoma. In this trial, lap-aroscopic lavage as treatment for patients withperforated diverticulitis Hinchey III disease was feasibleand safe in the short-term. In 2015, the results of SCAN-DIV study were published [75]. Among patients withlikely perforated diverticulitis and undergoing emergencysurgery, the use of laparoscopic lavage vs. primary resec-tion did not reduce severe postoperative complicationsand led to worse outcomes in secondary endpoints. Thesefindings do not support laparoscopic lavage for treatmentof perforated diverticulitis. In the same year, the result ofLADIES study was published. This showed that laparo-scopic lavage was not superior to sigmoidectomy for thetreatment of purulent perforated diverticulitis [76].After their publication, the results of the three studies

were summarized in six different meta-analyses, with simi-lar findings [77–82]. When compared with emergency sur-gery with resection, laparoscopic lavage in Hinchey IIIacute diverticulitis shows a comparable mortality but is as-sociated with a failure rate with a significantly augmentedneed for reoperation due to the failure of the treatment andto intra-abdominal abscess formation. Long-term resultswere similar, with no difference in morbidity and mortality.Several controversies remain about laparoscopic lavage

and drainage. It may be an acceptable alternative in se-lected patients [83]; however, it cannot be considered thefirst line treatment in patients with diverticular peritonitis.

Should primary anastomosis with or withoutprotecting stoma be preferred instead ofHartmann’s procedure in patients with diffuseperitonitis from diverticular perforation?We recommend Hartmann’s procedure (HP) for man-aging diffuse peritonitis in critically ill patients and in se-lected patients with multiple comorbidities (strongrecommendation based on low-quality evidence, 2B).

In clinically stable patients with no comorbidities, wesuggest primary resection with anastomosis with or with-out a diverting stoma (weak recommendation based onlow-quality evidence, 2B).HP has been considered the procedure of choice in pa-

tients with generalized peritonitis and remains a safetechnique for emergency colectomy in diverticular peri-tonitis, and is especially useful in critically ill patientsand in patients with multiple comorbidities. However,restoration of bowel continuity after a HP is associatedwith significant morbidity and resource utilization [84].As a result, many of these patients do not undergo re-versal surgery and remain with a permanent stoma [85].Common use of the HP in treating diverticular perfor-

ation worldwide is confirmed by a recent Australianstudy analyzing administrative data of patients withacute diverticulitis admitted, from 2009 to 2013, in eighttertiary referral centers with specialist colorectal services[86]. The HP was the most commonly performed emer-gency operation, accounting for 72% of resections.Another population-based retrospective cohort study

using administrative discharge data, conducted in On-tario, Canada, was published in 2014 [87]. Among 18,543 patients hospitalized with a first episode of diver-ticulitis, from 2002 to 2012, 3873 underwent emergencysurgery. The use of laparoscopy increased (9 to 18%, p <0.001), whereas the use of the HP remained unchanged(64%), and like in the Australian study, was the most fre-quently used operative approach in patients with compli-cated acute diverticulitis.In recent years, some authors have reported the role of

primary resection and anastomosis with or without a di-verting stoma, in the treatment of acute diverticulitis,even in the presence of diffuse peritonitis [88]. The deci-sion regarding the surgical choice in patients with diffuseperitonitis is generally left to the judgment of the sur-geon, who takes into account the clinical condition andthe comorbidities of the patient. Studies comparing mor-tality and morbidity of the HP versus primary anasto-mosis did not show any significant differences. However,most studies had relevant selection biases, as demon-strated by four systematic reviews [89–91].A study evaluating all patients with acute diverticulitis

undergoing emergent primary anastomosis with divert-ing loop ileostomy and HP was recently published usingthe ACS-NSQIP Colectomy Procedure Targeted Data-base from 2012 to 2016 [92]. Out of 130,963 patients,2729 patients were included. The median age was 64years, and 48.5% were male; the majority of patientsunderwent a HP, and only 208 (7.6%) underwent pri-mary anastomosis with diverting loop ileostomy. Patientsundergoing a HP had more comorbidities [e.g., COPD(9.8% vs. 4.8%, p = 0.017)], were more functionallydependent [6.3% vs. 2.4%, p = 0.025], and were more

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 10 of 18

unwell [e.g., septic shock (11.1% vs. 5.3%, p = 0.015)]compared to primary anastomosis with diverting loopileostomy patients. The mortality rates for the patientsundergoing a HP versus primary anastomosis with di-verting loop ileostomy were 7.6% and 2.9%, respectively(p = 0.011). The morbidity rates were 55.4% and 48.6%,respectively (p = 0.056). In multivariable analyses, com-pared to the HP, primary anastomosis with divertingloop ileostomy did not result in increased rates of mor-tality (OR = 0.21, 95% CI 0.03–1.58, p = 0.129) or mor-bidity (OR = 0.96, 95% CI 0.63–1.45, p = 0.834). Theauthors concluded that primary anastomosis with divert-ing loop ileostomy appears to be at least a safe alterna-tive to the HP for select patient populations needingemergent surgical management of acute diverticulitis.A comparison of primary resection and anastomosis with

or without defunctioning stoma to the HP as the optimaloperative strategy for patients presenting with Hincheystage III–IV was published by Constantinides et al. [93]. Atotal of 135 primary resection and anastomosis, 126 pri-mary anastomosis with defunctioning stoma, and 6619 HPswere considered in the study. Morbidity and mortality were55% and 30% for primary resection and anastomosis, 40%and 25% for primary anastomosis with defunctioningstoma, and 35% and 20% for the HP. Stomas remained per-manent in 27% of HPs and in 8% of primary anastomoseswith defunctioning stoma. The authors concluded that pri-mary anastomosis with defunctioning stoma may be theoptimal strategy for selected patients with diverticular peri-tonitis and may represent a good compromise betweenpostoperative adverse events, long-term quality of life, andrisk of permanent stoma.A small randomized trial of primary anastomosis with ile-

ostomy versus a HP in patients with diffuse diverticular peri-tonitis was published by Oberkofler et al. in 2012 [94]. Sixty-two patients with acute left-sided colonic perforation(Hinchey III and IV) from 4 centers were randomized toHartmann procedure (n = 30) and to primary anastomoseswith diverting ileostomy (n = 32). A planned stoma reversaloperation was performed after 3months in both groups. Thestudy reported no difference in initial mortality and morbid-ity (mortality 13% vs. 9% and morbidity 67% vs. 75% in theHP vs. primary anastomosis), but a reduction in length ofstay, lower costs, fewer serious complications, and greaterstoma reversal rates in the primary anastomosis group.A multicenter RCT conducted between June 2008 and

May 2012, the DIVERTI (Primary vs. Secondary Anasto-mosis for Hinchey Stage III-IV Diverticulitis) trial [95],was published in 2017. All 102 patients enrolled werecomparable for age (p = 0.4453), sex (p = 0.2347), Hincheystage III vs. IV (p = 0.2347), and Mannheim PeritonitisIndex (p = 0.0606). Overall mortality did not differ signifi-cantly between the HP (7.7%) and primary anastomosis(4%) (p = 0.4233) groups. Morbidity for both resection

and stoma reversal operations was comparable (39% inthe HP arm vs. 44% in the primary anastomosis arm; p =0.4233). At 18months, 96% of primary anastomosis pa-tients and 65% of the HP patients had a stoma reversal (p= 0.0001). Although mortality was similar in both arms,the rate of stoma reversal was significantly higher in theprimary anastomosis arm. This trial provides additionalevidence in favor of primary anastomosis with divertingileostomy over the HP in patients with diverticularperitonitis.In 2019, the results of the LADIES study [96] demon-

strated that in hemodynamically stable, immunocompe-tent patients younger than 85 years, primary anastomosisis preferable to the HP as a treatment for perforated di-verticulitis (Hinchey III or Hinchey IV disease). Patientsaged between 18 and 85 years who presented with clin-ical signs of general peritonitis and suspected perforateddiverticulitis were eligible for inclusion if plain abdom-inal radiography or CT scan showed diffuse free gas orfluid. Patients with Hinchey I or II diverticulitis were noteligible for inclusion. Patients were allocated (1:1) to theHP or sigmoidectomy with primary anastomosis, with orwithout defunctioning ileostomy. The 12-month stoma-free survival was significantly better for patients under-going primary anastomosis compared with the HP(94.6% [95% CI 88.7–100] vs. 71.7% [95% CI 60.1–83·3],hazard ratio 2.79 [95% CI 1·86–4.18]; log-rank p <0·0001). There were no significant differences in short-term morbidity and mortality after the index procedurefor the HP compared with primary anastomosis (mor-bidity, 29 [44%] of 66 patients vs. 25 [39%] of 64, p =0.60; mortality, two [3%] vs. four [6%], p = 0.44).Recently, a systematic review of the existing literature

about surgical management of Hinchey III and IV diver-ticulitis was published [97]. A total of 25 studies involv-ing 3546 patients were included in this study. Theoverall mortality in patients undergoing a HP was 10.8%across the observational studies and 9.4% in the RCTs.The mortality rate in patients undergoing a primaryanastomosis was lower than that in the HP group, at8.2% in the observational studies and 4.3% in the RCTs.A comparison of primary anastomosis with the HP dem-onstrated a 40% lower mortality rate in the primaryanastomosis group than in the HP group (OR 0.60, 95%CI 0.38–0.95, p = 0.03), when analyzing the observa-tional studies. However, meta-analysis of the RCTs didnot demonstrate any difference in mortality. Wound in-fection rates between the two groups were comparable.

Should laparoscopic resection be preferred toopen resection in patients with diffuse peritonitisdue to perforated diverticulitis?In patients with diffuse peritonitis due to perforated di-verticulitis, we suggest to perform an emergency

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 11 of 18

laparoscopic sigmoidectomy only if technical skills andequipment are available (weak recommendation basedon low-quality evidence, 2C).Laparoscopic sigmoidectomy for diverticulitis had ini-

tially been confined to the elective setting. However, inphysiologically stable patients, laparoscopic sigmoidect-omy may be feasible in the setting of purulent and fecaldiverticular peritonitis. In 2015, a systematic review onlaparoscopic sigmoidectomy for diverticulitis in theemergency setting was published [98].The review included 4 case series and one cohort

study (total of 104 patients) out of 1706 references. AHP was performed in 84 patients, and primary anasto-mosis was fashioned in 20 patients. The mean operatingtime varied between 115 and 200 min. The conversionto open surgery rate varied between 0 and 19%. Themean length of hospital stay ranged between 6 and 16days. Surgical re-intervention was necessary in 2 pa-tients. In 20 patients operated upon without defunction-ing ileostomy, no anastomotic leakage was reported.Three patients died during the postoperative period.Stoma reversal after HP was performed in 60 out of 79evaluable patients (76%).These guidelines are limited by the low-quality evi-

dence that showed that emergency laparoscopic sigmoi-dectomy for the treatment of perforated diverticulitiswith generalized peritonitis is feasible. These studies oc-curred in selected patients and in experienced units andare not generalizable to all centers. High-quality pro-spective or randomized studies are needed to demon-strate benefits of emergency laparoscopic sigmoidectomycompared to open sigmoidectomy for perforateddiverticulitis.

Should damage control surgery with stagedlaparotomies be recommended in patients withacute peritonitis due to diverticular perforation?We suggest damage control surgery (DCS) with stagedlaparotomies in selected unstable patients with diffuseperitonitis due to diverticular perforation (weak recom-mendation based on low-quality evidence, 2C).A damage control surgical strategy may be useful for

patients in physiological extremis from abdominal sepsis[99]. The initial surgery focuses on control of the sepsis,and a subsequent operation deals with the anatomicalrestoration of the gastrointestinal tract, after a period ofphysiological resuscitation. This strategy facilitates boththe control of the severe sepsis control as well as poten-tially improving the rate of primary anastomosis [100].Generalized diverticular peritonitis is a life-threatening

condition requiring prompt emergency operation. Toimprove outcomes and reduce the rate of colostomy for-mation, a new algorithm for damage control operation,lavage, limited resection or closure of perforation, and

second look surgery to restore intestinal continuity wasdeveloped in recent years [101, 102]. Some patients maybe physiologically deranged. These patients, who arehemodynamically unstable, are not optimal candidatesfor immediate complex operative interventions. Afterinitial surgery, which should be limited to source con-trol, e.g., primary closure of the perforation/local resec-tion of the diseased bowel, the patient is taken to theintensive care unit (ICU) for physiologic optimization.However, this strategy will also delay bowel anastomosisto a period of physiological stability [103] potentiallychanging the intraoperative physiological milieu, poten-tially favoring a primary anastomosis, and avoiding theformation of a stoma altogether. In the setting of acutediverticulitis, several reports (with low level of evidence)were published. In 2010, a prospective observationalstudy was published by Kafka-Ritsch et al. [101]. A totalof 51 patients (28 females 55%) with a median age of 69(range 28–87) years, with perforated diverticulitisHinchey III (n = 40, 78%) or Hinchey IV (n = 11, 22%),were prospectively enrolled in the study. Patients wereinitially managed with limited resection, lavage, and tem-porary abdominal closure followed by second, recon-structive operation 24–48 h later, which are supervisedby a colorectal surgeon. Bowel continuity was restoredin 38 (84%) patients, of which four were protected by aloop ileostomy. Five anastomotic leaks (13%) were en-countered requiring loop ileostomy in two patients anda HP in remaining three patients. The overall mortalityrate was 9.8%, and 35 of 46 surviving patients (76%) leftthe hospital with reconstructed colon continuity. Fascialclosure was achieved in all patients.Sohn et al. performed a case-control study comparing

traditional strategy versus damage control: there were nodifferences in morbidity and mortality, but there was asignificant reduction of stoma creation in the damagecontrol group [104].Despite promising experiences, little robust or large-

scale data are available, and the open abdomen anddamage control strategy are not without risk: for ex-ample, such procedures are associated with the forma-tion of entero-atmospheric fistula and high costs, amongother issues. Guidelines recommend this strategy only incritically ill patients who cannot withstand major sur-gery. Although there is now a biologic rationale for suchan intervention as well as non-standardized and erraticclinical utilization, this remains a novel therapy with po-tential side effects and clinical equipoise. The WSES rec-ommends to use an open abdomen approach in selectedsignificantly physiologically deranged patients with on-going sepsis [105]. The Closed Or Open after Laparot-omy (COOL) study constitutes a prospective RCT thatwill randomly allocate eligible surgical patients intraop-eratively to either formal closure of the fascia or use of

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 12 of 18

the open abdomen with application of with active negativeperitoneal pressure therapy. This trial will be powered todemonstrate a mortality difference in this highly lethaland morbid condition to ensure critically ill patients arereceiving the best care possible and not being harmed byinappropriate therapies based on opinion only [106].

What factors should be considered in planningelective resection in cases of acute diverticulitistreated non-operatively?We suggest evaluating patient-related factors and notnumber of previous episodes of diverticulitis in planningelective sigmoid resection (weak recommendation basedon very low-quality evidence, 2D).After an episode of ALCD treated conservatively, we sug-

gest planning of an elective sigmoid resection in high-riskpatients, such as immunocompromised patients (weak rec-ommendation based on very low-quality evidence, 2D).Recurrence of acute diverticulitis is lower than previously

thought. Historically, it has been reported that about onethird of all patients with acute diverticulitis will have a re-current attack, often within 1 year [107, 108]. However, therecurrence after an uncomplicated episode of diverticulitisappears much lower: with a recent prospective study re-ported a recurrence of only 1.7% over 5 years of follow-up[109, 110]. After a follow-up of 4 years, El Sayed et al. [111],in an English study of over 65,000 patients managed non-operatively for their first episode of diverticulitis, found therecurrence rate to be around 11.2%. Emergency and electivecolectomy rates were 0.9 and 0.75%, respectively. Femalegender, young age, smoking, obesity, and complicated initialdisease were risk factors for readmission and emergencysurgery. The study also pointed out that some factors asso-ciated with recurrence are modifiable; weight reduction andsmoking cessation can be championed.In 2014, a systematic review of studies reviewing the

diagnosis and management of chronic and recurrent di-verticulitis (from studies published between January 2000to March 2013) was published [112]. The 68 studies in-cluded were almost exclusively observational and had lim-ited certainty of treatment effect. The authors found thatcomplicated recurrence after recovery from an uncompli-cated episode of diverticulitis was rare (< 5%) and that ageat onset younger than 50 years and 2 or more recurrencesdid not increase the risk of complications.The authors concluded that the indication for elective

colectomy following 2 episodes of diverticulitis is no lon-ger accepted. Indication to colectomy should be madebased on consideration of the risks of recurrent diver-ticulitis, the morbidity of surgery, ongoing symptoms,the complexity of disease, and operative risk.A recent open-label randomized multicenter trial (DIR-

ECT trial) randomized 109 patients from 24 teaching andtwo academic hospitals in the Netherlands presenting with

recurrent and persisting abdominal complaints after anepisode of diverticulitis to receive surgical treatment ornon-operative management [113]. After a brief follow-upof 6months, elective sigmoidectomy resulted in a betterquality of life (assessed by many specific questionnaires)compared to non-operative management. However, theresults of the study may be affected by the heterogeneityof patients enrolled (patients with both recurrent diver-ticulitis and patients with persistent abdominalcomplaints).Currently, the decision to perform an elective resec-

tion after one or more episodes of AD should be under-taken on a case-by-case basis, taking into account riskfactors, complications, age, and severity of episodes aswell as the patient’s personal circumstances and comor-bidities (e.g., immunosuppressed patients) [114].

What is the optimal antibiotic therapy forpatients with diffuse peritonitis due todiverticular perforation? What is the optimalduration of antibiotic therapy after surgicalsource control in diffuse peritonitis due todiverticular perforation?We suggest to choose the empirically designed antibioticregimen on the basis of the underlying clinical conditionof the patient, the pathogens presumed to be involved,and the risk factors for major antimicrobial resistancepatterns (strong recommendation based on moderate-quality evidence, 1B).We suggest a 4-day period of postoperative antibiotic

therapy in complicated ALCD if source control has beenadequate (weak recommendation based on moderate-quality evidence, 2B).Antibiotic therapy plays an important role in the man-

agement of complicated acute diverticulitis. Typically, itis an empiric antibiotic treatment. The regimen shoulddepend on the severity of infection, the pathogens pre-sumed to be involved, and the risk factors indicative ofmajor resistance patterns [39]. Several recommendationshave been recently published in literature [39]. However,consideration of local epidemiological data and resist-ance profiles is essential for antibiotic selection.Considering intestinal microbiota of large bowel acute di-

verticulitis requires antibiotic coverage for Gram-positiveand Gram-negative bacteria, as well as for anaerobes. Mostof the complicated acute diverticulitis is mainly acommunity-acquired infection. The main resistance threatin IAIs is posed by extended-spectrum beta-lactamase(ESBL)-producing Enterobacteriaceae, which are becomingincreasingly common in community-acquired infectionsworldwide [33]. The most significant risk factors for ESBL-producing pathogens include prior exposure to antibioticsand comorbidities requiring concurrent antibiotic therapy[39]. Anti-ESBL-producer coverage should be warranted

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 13 of 18

for patients with these risk factors. Discontinuation of anti-biotic treatment should be at 4 days from source control asthis has been demonstrated as non-inferior to longer ther-apy based on the STOP IT trial [115].The recent prospective trial by Sawyer et al. demon-

strated that in patients with complicated IAIs undergoingan adequate source-control procedure, the outcomes afterapproximately 4 days fixed-duration antibiotic therapy weresimilar to those after a longer course of antibiotics that ex-tended until after the resolution of physiological abnormal-ities [115].Patients who have signs of sepsis beyond 5 to 7days of adequate antibiotic treatment warrant aggressivediagnostic investigation in search of a reservoir of infection.

Which are the principles of the treatment of acuteright-sided colonic diverticulitis?Although studies have shown that the percentage of com-plications requiring surgery is higher in patients withALCD than in patients with ARCD, the principles ofdiagnosis and treatment of patients with ARCD are simi-lar to those with ALCD. We suggest that all the state-ments for ALCD also apply to ARCD.Acute colonic diverticulitis is a common condition af-

fecting the adult population. Traditionally, the sigmoidcolon is considered the most commonly involved part,and ARCD is much rarer [116]. However, in some re-gions of the world, ARCD outnumber ALCD [116]. TheARCD differs from the ALCD in some aspects. Theformer is usually solitary [29, 117], and has a low rate ofcomplicated diverticulitis [118].ARCD generally occurs in middle-aged men, and its

incidence does not increase with age. Especially theARCD located in the cecum, it is difficult to distinguishARCD from acute appendicitis because of their similarsymptoms and signs.CT scanning appears to be the best overall imaging mo-

dality in the diagnosis of possible ARCD [119, 120]. How-ever, US is more economic than CT and poses no radiation,which may be particularly important since the patients hav-ing right-sided diverticulitis are relatively younger.US features, including diverticular wall thickening, sur-

rounding echogenic fat, and intra-diverticular echogenicmaterial, can provide clear information for making cor-rect preoperative diagnosis. However, US is operatordependent. Ambiguous US studies may be complemen-ted with a contrast-enhanced CT [121].Currently, the management of ARCD is not well de-

fined, and no unique guidelines have been proposed.Although previous studies have shown that the per-

centage of complications requiring surgery is higher inpatients with ALCD than in patients with ARCD [122],the principles of diagnosis and treatment of ARCD arevery similar to those of ALCD. As a treatment option,non-operative methods should be preferred, in cases

without diffuse peritonitis although differentiating benignand malignant cases pre-operatively is often difficult [123].Surgical treatment is usually used in the treatment ofcomplicated cases [116, 124, 125]. Resection of the in-flamed colon with primary anastomosis can be performedby laparoscopy in experienced centers [126].

ConclusionsALCD is a common problem encountered by Westernsurgeons in the acute setting. The sigmoid is usually themost commonly involved colonic segment, while ARCD ismuch rarer.An international multidisciplinary panel of experts from

the World Society of Emergency Surgery (WSES) updatedits guidelines on the management of acute left-sided co-lonic (ALCD) diverticulitis according to the most recentavailable literature. The update includes recent changesintroduced in the management of ALCD. The new updatecontains a section on ARCD, which is more prevalent thanALCD in some regions of the world.

AbbreviationsALCD: Acute left-sided colonic diverticulitis; ARCD: Acute right-sided diver-ticulitis; CRC: Colorectal cancer; CRP: C-reactive protein; CT: Computedtomography; DCS: Damage control surgery; ESBL: Extended-spectrum beta-lactamase; HP: Hartmann’s procedure; IAIs: Intra-abdominal infections;ICU: Intensive care unit; IMS: Immunosuppression; RCT: Randomizedcontrolled trial; US: Ultrasound; WBC: White blood cell; WSES: World Societyof Emergency Surgery

AcknowledgementsNot applicable.

Authors’ contributionsMS wrote the first draft of the manuscript. All authors reviewed andapproved the manuscript.

FundingNo funding sources to disclose.

Availability of data and materialsNot applicable.

Ethics approval and consent to participateNot applicable.

Consent for publicationNot applicable.

Competing interestsThe authors declare that they have no competing interests.

Author details1Department of Surgery, Macerata Hospital, Macerata, Italy. 2Department ofGeneral Surgery, Royal Perth Hospital, The University of Western Australia,Perth, Australia. 3Department of General Surgery, Division of Surgery,Rambam Health Care Campus, Haifa, Israel. 4General Surgery Department,Bufalini Hospital Hospital, Cesena, Italy. 5General, Emergency and TraumaSurgery Department, Pisa University Hospital, Pisa, Italy. 6Department ofSurgery, College of Medicine and Health Sciences, UAE University, Al-Ain,United Arab Emirates. 7Department of Surgery, University Hospital CentreZagreb, Zagreb, Croatia. 8Trauma Surgery Department, Scripps MemorialHospital, La Jolla, CA, USA. 9Surgical Department and ICU Department,General Hospital of Larissa, Larissa, Greece. 10Department of EmergencySurgery, Parma Maggiore Hospital, Parma, Italy. 11Department of General and

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 14 of 18

Emergency Surgery, ASST, San Gerardo Hospital, Monza, Italy. 12School ofMedicine and Surgery, University of Milan-Bicocca, Milan, Italy. 13GeneralSurgery and Trauma Team, University of Milano, ASST Niguarda Milano,Milan, Italy. 14Riverside University Health System Medical Center, Loma LindaUniversity School of Medicine, Moreno Valley, CA, USA. 15Emergency SurgeryUnit, San Filippo Neri Hospital, Rome, Italy. 16Department of Surgery, TianjinNankai Hospital, Nankai Clinical School of Medicine, Tianjin MedicalUniversity, Tianjin, China. 17Department of Surgery, Royal Infirmary ofEdinburgh, Edinburgh, UK. 18Gastroenterology and Endoscopy Unit,University Hospital of Parma, Parma, Italy. 19Department of Surgery, UniversityClinical Center of Tuzla, Tuzla, Bosnia and Herzegovina. 20DepartmentGeneral Surgery, Kipshidze Central University Hospital, Tbilisi, Georgia.21Department of Digestive Surgery, Guastalla Hospital, Reggio Emilia, Italy.22General Surgery, Versilia Hospital, UslNordovest, Tuscany, Italy. 23ColorectalUnit, Addenbrooke’s Hospital, Cambridge University Hospitals NHSFoundation Trust, Cambridge, UK. 24Envision Healthcare, Dallas, TX, USA.25Department of General Surgery, Trauma and Emergency Surgery Division,ABC Medical School, Santo André, SP, Brazil. 26Trauma/Acute Care Surgery &Surgical Critical Care, University of Campinas, Campinas, Brazil. 27SecondDepartment of Surgery, Aretaieion University Hospital, National andKapodistrian University of Athens, Athens, Greece. 28Department of Surgery,Hospital Universitário Terezinha de Jesus, Faculdade de Ciências Médicas eda Saúde de Juiz de Fora, Juiz de Fora, Brazil. 29Trauma Service, Inkosi AlbertLuthuli Central Hospital and Department of Surgery, Nelson R MandelaSchool of Clinical Medicine, Durban, South Africa. 30Department of Generaland Thoracic Surgery, University Hospital Giessen, Giessen, Germany. 31Clinicfor Emergency Surgery, Medical Faculty, University of Belgrade, Belgrade,Serbia. 32Department of Surgery, Assia Medical Group, Tel Aviv UniversitySackler School of Medicine, Tel Aviv, Israel. 33Department of EmergencySurgery, City Hospital, Mozyr, Belarus. 34General, Acute Care, Abdominal WallReconstruction, and Trauma Surgery, Foothills Medical Centre, Calgary, AB,Canada. 35Department of Surgery, The Brunei Cancer Centre, Jerudong Park,Brunei. 36Division of Acute Care Surgery and Surgical Critical Care,Department of Surgery, Los Angeles County and University of SouthernCalifornia Medical Center, University of Southern California, Los Angeles, CA,USA. 37Department of General Surgery, Faculty of Medicine, ErzincanUniversity, Erzincan, Turkey. 38Global Alliance for Infections in Surgery, Porto,Portugal. 39Department of Surgery, Westchester Medical Center, New YorkMedical College, Valhalla, NY, USA. 40Abdominal Center, University HospitalMeilahti, Helsinki, Finland. 41Surgical Disciplines, Immanuel Kant Baltic FederalUniversity/Regional Clinical Hospital, Kaliningrad, Russian Federation.42Department of Surgery, School of Medicine, Washington University, SaintLouis, USA. 43Department of Surgery, University of Washington, Seattle, WA,USA. 44Department of Surgery, Post-Graduate Institute of Medical Sciences,Rohtak, India. 45Department of Surgery, Radiology, University Hospital of theWest Indies, Kingston, Jamaica. 46Department of Surgery, Denver HealthMedical Center, University of Colorado, Denver, CO, USA. 47Department ofSurgery, Division of Acute Care Surgery, and Center for Sepsis and CriticalIllness Research, University of Florida College of Medicine, Gainesville, FL,USA. 48Department of Surgery, Emergency Hospital of Bucharest, Bucharest,Romania. 49Infectious Diseases Unit, Bolzano Central Hospital, Bolzano, Italy.50Department of Surgery, Anadolu Medical Center, Kocaali, Turkey. 51GeneralSurgery Department, Colorectal Surgery Unit, La Paz University Hospital,Madrid, Spain. 52General Surgery Department, Medical University, UniversityHospital St George, Plovdiv, Bulgaria. 53Department of Aeromedical Servicesfor Emergency and Trauma Care, Ehime University Graduate School ofMedicine, Ehime, Japan. 54Emergency Surgery, Fondazione PoliclinicoUniversitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome,Italy. 55First Department of Surgery, First Faculty of Medicine, CharlesUniversity in Prague and General University Hospital in Prague, Prague,Czech Republic. 56Department of Surgery, MOSC Medical College Kolenchery,Cochin, India.

Received: 10 January 2020 Accepted: 29 April 2020

References1. Weizman AV, Nguyen GC. Diverticular disease: epidemiology and

management. Can J Gastroenterol. 2011;25:385–9.2. Schoetz DJ. Diverticular disease of the colon: a century-old problem. Dis

Colon Rectum. 1999;42:703–9.

3. Shahedi K, Fuller G, Bolus R, Cohen E, Vu M, Shah R, et al. Long-term risk ofacute diverticulitis among patients with incidental diverticulosis foundduring colonoscopy. Clin Gastroenterol Hepatol. 2013;11:1609–13.

4. Collins D, Winter DC. Modern concepts in diverticular disease. J ClinGastroenterol. 2015;49:358–69.

5. Warner E, Crighton EJ, Moineddin R, Mamdani M, Upshur R. Fourteen-yearstudy of hospital admissions for diverticular disease in Ontario. Can JGastroenterol. 2007;21:97–9.

6. Jamal Talabani A, Lydersen S, Endreseth BH, Edna TH. Major increase inadmission- and incidence rates of acute colonic diverticulitis. Int J Color Dis.2014;29:937–45.

7. Sartelli M, Catena F, Ansaloni L, Coccolini F, Griffiths EA, Abu-Zidan FM, et al.WSES guidelines for the management of acute left sided colonicdiverticulitis in the emergency setting. World J Emerg Surg. 2016;11:37.

8. Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Alonso-Coello P, et al.GRADE: an emerging consensus on rating quality of evidence and strengthof recommendations. BMJ. 2008;336:924–6.

9. Brozek JL, Akl EA, Jaeschke R, Lang DM, Bossuyt P, Glasziou P, et al. Gradingquality of evidence and strength of recommendations in clinical practiceguidelines: part 2 of 3. The GRADE approach to grading quality of evidenceabout diagnostic tests and strategies. Allergy. 2009;64:1109–16.

10. Hinchey EJ, Schaal PH, Richards MB. Treatment of perforated diverticulardisease of the colon. Adv Surg. 1978;12:85–109.

11. Neff CC, van Sonnenberg E. CT of diverticulitis. Diagnosis and treatment.Radiol Clin N Am. 1989;27:743–52.

12. Ambrosetti P, Becker C, Terrier F. Colonic diverticulitis: impact of imaging onsurgical management—a prospective study of 542 patients. Eur Radiol.2002;12:1145–9.

13. Kaiser AM, Jiang JK, Lake JP, Ault G, Artinyan A, Gonzalez-Ruiz C, et al. Themanagement of complicated diverticulitis and the role of computedtomography. Am J Gastroenterol. 2005;100:910–7.

14. Mora Lopez L, Serra Pla S, Serra-Aracil X, Ballesteros E, Navarro S. Applicationof a modified Neff classification to patients with uncomplicateddiverticulitis. Color Dis. 2013;15:1442–7.

15. Sallinen VJ, Leppäniemi AK, Mentula PJ. Staging of acute diverticulitis basedon clinical, radiologic, and physiologic parameters. J Trauma Acute CareSurg. 2015;78:543–51.

16. Toorenvliet BR, Bakker RF, Breslau PJ, Merkus JW, Hamming JF. Colonicdiverticulitis: a prospective analysis of diagnostic accuracy and clinicaldecision-making. Color Dis. 2010;12:179–86.

17. Laméris W, van Randen A, van Gulik TM, Busch OR, Winkelhagen J, BossuytPM, et al. A clinical decision rule to establish the diagnosis of acutediverticulitis at the emergency department. Dis Colon Rectum. 2010;53:896–904.

18. Andeweg CS, Knobben L, Hendriks JC, Bleichrodt RP, van Goor H. How todiagnose acute left-sided colonic diverticulitis: proposal for a clinical scoringsystem. Ann Surg. 2011;253:940–6.

19. Kechagias A, Rautio T, Kechagias G, Mäkelä J. The role of C-reactive proteinin the prediction of the clinical severity of acute diverticulitis. Am Surg.2014;80:391–5.

20. Van de Wall BJ, Draaisma WA, van der Kaaij RT, Consten EC, Wiezer MJ,Broeders IA. The value of inflammation markers and body temperature inacute diverticulitis. Color Dis. 2013;15:621–6.

21. Mäkelä JT, Klintrup K, Takala H, Rautio T. The role of C-reactive protein inprediction of the severity of acute diverticulitis in an emergency unit. ScandJ Gastroenterol. 2015;50:536–41.

22. Kechagias A, Sofianidis A, Zografos G, Leandros E, Alexakis N, Dervenis C.Index C-reactive protein predicts increased severity in acute sigmoiddiverticulitis. Ther Clin Risk Manag. 2018;14:1847–53.

23. Gewurz H, Mold C, Siegel J, Fiedel B. C-reactive protein and the acute phaseresponse. Adv Intern Med. 1982;27:345–72.

24. Laméris W, van Randen A, Bipat S, Bossuyt PM, Boermeester MA, Stoker J. Gradedcompression ultrasonography and computed tomography in acute colonicdiverticulitis: meta- analysis of test accuracy. Eur Radiol. 2008;18:2498–511.

25. Liljegren G, Chabok A, Wickbom M, Smedh K, Nilsson K. Acute colonicdiverticulitis: a systematic review of diagnostic accuracy. Color Dis. 2007;9:480–8.

26. Ambrosetti P, Jenny A, Becker C, Terrier TF, Morel P. Acute left colonicdiverticulitis–compared performance of computed tomography and water-soluble contrast enema: prospective evaluation of 420 patients. Dis ColonRectum. 2000;43:1363–7.

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 15 of 18

27. Sartelli M, Moore FA, Ansaloni L, Di Saverio S, Coccolini F, Griffiths EA, et al.A proposal for a CT driven classification of left colon acute diverticulitis.World J Emerg Surg. 2015;10:3.

28. Mazzei MA, Cioffi Squitieri N, Guerrini S, Stabile Ianora AA, Cagini L, MacariniL, et al. Sigmoid diverticulitis: US findings. Crit Ultrasound J. 2013;5(Suppl 1):S1–5.

29. Puylaert JB. Ultrasound of colon diverticulitis. Dig Dis. 2012;30:56–9.30. Andeweg CS, Wegdam JA, Groenewoud J, van der Wilt GJ, van Goor H,

Bleichrodt RP. Toward an evidence-based step-up approach in diagnosingdiverticulitis. Scand J Gastroenterol. 2014;49:775–84.

31. Laméris W, van Randen A, van Es HW, van Heesewijk JP, van Ramshorst B,Bouma WH, et al. OPTIMA study group: imaging strategies for detection ofurgent conditions in patients with acute abdominal pain: diagnosticaccuracy study. BMJ. 2009;338:b2431.

32. Heverhagen JT, Sitter H, Zielke A, Klose KJ. Prospective evaluation of thevalue of magnetic resonance imaging in suspected acute sigmoiddiverticulitis. Dis Colon Rectum. 2008;51:1810–5.

33. Halpenny DF, McNeil G, Snow A, Geoghegan T, Torreggiani WC. Prospectiveevaluation of the value of magnetic resonance imaging in suspected acutesigmoid diverticulitis. Dis Colon Rectum. 2009;52:1030–1.

34. Hwang SS, Cannom RR, Abbas MA, Etzioni D. Diverticulitis in transplantpatients and patients on chronic corticosteroid therapy: a systematic review.Dis Colon Rectum. 2010;53:1699–707.

35. Dalla Valle R, Capocasale E, Mazzoni MP, Busi N, Benozzi L, Sivelli R, et al.Acute diverticulitis with colon perforation in renal transplantation.Transplant Proc. 2005;37:2507–10.

36. Qasabian RA, Meagher AP, Lee R, Dore GJ, Keogh A. Severe diverticulitisafter heart, lung, and heart-lung transplantation. J Heart Lung Transplant.2004;23:845–9.

37. Lederman ED, Conti DJ, Lempert N, Singh TP, Lee EC. Complicateddiverticulitis following renal transplantation. Dis Colon Rectum. 1998;41:613–8.

38. Bordeianou L, Hodin R. Controversies in the surgical management ofsigmoid diverticulitis. J Gastrointest Surg. 2007;11:542–8.

39. Biondo S, Trenti L, Elvira J, Golda T, Kreisler E. Outcomes of colonicdiverticulitis according to the reason of immunosuppression. Am J Surg.2016;21:384–90.

40. Sartelli M, Chichom-Mefire A, Labricciosa FM, Hardcastle T, Abu-Zidan FM,Adesunkanmi AK, et al. The management of intra-abdominal infections froma global perspective: 2017 WSES guidelines for management of intra-abdominal infections. World J Emerg Surg. 2017;12:29. Erratum in: World JEmerg Surg. 2017;12:36.

41. Shabanzadeh DM, Wille-Jørgensen P. Antibiotics for uncomplicateddiverticulitis. Cochrane Database Syst Rev. 2012;11:CD009092.

42. Chabok A, Påhlman L, Hjern F, Haapaniemi S, Smedh K, AVOD Study Group.Randomized clinical trial of antibiotics in acute uncomplicated diverticulitis.Br J Surg. 2012;99:532–9.

43. Mali JP, Mentula PJ, Leppäniemi AK, Sallinen VJ. Symptomatic treatment foruncomplicated acute diverticulitis: a prospective cohort study. Dis ColonRectum. 2016;59:529–34.

44. Daniels L, Ünlü Ç, de Korte N, van Dieren S, Stockmann HB, Vrouenraets BC,et al. Randomized clinical trial of observational versus antibiotic treatmentfor a first episode of CT-proven uncomplicated acute diverticulitis. Br J Surg.2017;104:52–61.

45. van Dijk ST, Daniels L, Ünlü Ç, de Korte N, van Dieren S, Stockmann HB,et al. Long-term effects of omitting antibiotics in uncomplicated acutediverticulitis. Am J Gastroenterol. 2018;113:1045–52.

46. Sartelli M, Viale P, Catena F, Ansaloni L, Moore E, Malangoni M, et al. 2013WSES guidelines for management of intra-abdominalinfections. World JEmerg Surg. 2013;8:3.

47. Ridgway PF, Latif A, Shabbir J, Ofriokuma F, Hurley MJ, Evoy D, et al.Randomized controlled trial of oral vs intravenous therapy for the clinicallydiagnosed acute uncomplicated diverticulitis. Color Dis. 2009;11:941–6.

48. Fozard JB, Armitage NC, Schofield JB, Jones OM. Association ofColoproctology of Great Britain and Ireland. ACPGBI position statement onelective resection for diverticulitis. Color Dis. 2011;13:1–11.

49. Etzioni DA, Chiu VY, Cannom RR, Burchette RJ, Haigh PI, Abbas MA.Outpatient treatment of acute diverticulitis: rates and predictors of failure.Dis Colon Rectum. 2010;53:861–5.

50. Jackson JD, Hammond T. Systematic review: outpatient management ofacute uncomplicated diverticulitis. Int J Color Dis. 2014;29:775–81.

51. Rodrìguez-Cerrillo M, Poza-Montoro A, Fernandez-Diaz E, Matesanz-David M,Inurrieta RA. Treatment of elderly patients with uncomplicated diverticulitis,even with comorbidity, at home. Eur J Intern Med. 2013;24:430–2.

52. Biondo S, Golda T, Kreisler E, Espin E, Vallribera F, Oteiza F, et al. Outpatientversus hospitalization management for uncomplicated diverticulitis: aprospective, multicenter randomized clinical trial (DIVER trial). Ann Surg.2014;259:38–44.

53. Cirocchi R, Randolph JJ, Binda GA, Gioia S, Henry BM, Tomaszewski KA, et al.Is the outpatient management of acute diverticulitis safe and effective? Asystematic review and meta-analysis. Tech Coloproctol. 2019;23:87–100.

54. Balasubramanian I, Fleming C, Mohan HM, Schmidt K, Haglind E, Winter DC.Out-patient management of mild or uncomplicated diverticulitis: asystematic review. Dig Surg. 2017;34:151–60.

55. Bolkenstein HE, van Dijk ST, Consten ECJ, Heggelman BGF, Hoeks CMA,Broeders IAMJ, et al. Conservative treatment in diverticulitis patients withpericolicextraluminal air and the role of antibiotic treatment. J GastrointestSurg. 2019;23:2269–76.

56. Andersen JC, Bundgaard L, Elbrønd H, Laurberg S, Walker LR, Støvring J,et al. Danish national guidelines for treatment of diverticular disease. DanMed J. 2012;59:C4453.

57. Gregersen R, Mortensen LQ, Burcharth J, Pommergaard HC, Rosenberg J.Treatment of patients with acute colonic diverticulitis complicated byabscess formation: a systematic review. Int J Surg. 2016;35:201–8.

58. Ambrosetti P, Chautems R, Soravia C, Peiris-Waser N, Terrier F. Long-termoutcome of mesocolic and pelvic diverticular abscesses of the left colon: aprospective study of 73 cases. Dis Colon Rectum. 2005;48:787–91.

59. Brandt D, Gervaz P, Durmishi Y, Platon A, Morel P, Poletti PA. PercutaneousCT scan guided drainage versus antibiotherapy alone for Hinchey IIdiverticulitis: a case-control study. Dis Colon Rectum. 2006;49:1533–8.

60. Siewert B, Tye G, Kruskal J, Sosna J, Opelka F, Raptopoulos V, et al. Impact ofCT-guided drainage in the treatment of diverticular abscesses: size matters.AJR. 2006;186:680–6.

61. Singh B, May K, Coltart I, Moore NR, Cunningham C. The long-term resultsof percutaneous drainage of diverticular abscess. Ann R Coll Surg Engl.2008;90:297–301.

62. Kumar RR, Kim JT, Haukoos JS, Macias LH, Dixon MR, Stamos MJ, et al.Factors affecting the successful management of intra-abdominal abscesseswith antibiotics and the need for percutaneous drainage. Dis Colon Rectum.2006;49:183–9.

63. Elagili F, Stocchi L, Ozuner G, Kiran RP. Antibiotics alone instead ofpercutaneous drainage as initial treatment of large diverticular abscess.Tech Coloproctol. 2015;19:97–103.

64. Tsai HL, Hsieh JS, Yu FJ, Wu DC, Chen FM, Huang CJ, et al. Perforated coloniccancer presenting as intra-abdominal abscess. Int J Color Dis. 2007;22:15–9.

65. Yeo ES, Ng KH, Eu KW. Perforated colorectal cancer: an importantdifferential diagnosis in all presumed diverticular abscesses. Ann Acad MedSingap. 2011;40:375–8.

66. de Vries HS, Boerma D, Timmer R, van Ramshorst B, Dieleman LA, vanWestreenen HL. Routine colonoscopy is not required in uncomplicateddiverticulitis: a systematic review. Surg Endosc. 2014;28:2039–47.

67. Sharma PV, Eglinton T, Hider P, Frizelle F. Systematic review and meta-analysis of the role of routine colonic evaluation after radiologicallyconfirmed acute diverticulitis. Ann Surg. 2014;259:263–72.

68. Sallinen V, Mentula P, Leppäniemi A. Risk of colon cancer after computedtomography-diagnosed acute diverticulitis: is routine colonoscopynecessary? Surg Endosc. 2014;28:961–5.

69. Feingold D, Steele SR, Lee S, Kaiser A, Boushey R, Buie WD, et al. Practiceparameters for the treatment of sigmoid diverticulitis. Dis Colon Rectum.2014;57:284–94.

70. Dharmarajan S, Hunt SR, Birnbaum EH, Fleshman JW, Mutch MG. Theefficacy of nonoperative management of acute complicated diverticulitis.Dis Colon Rectum. 2011;54:663–71.

71. Sallinen VJ, Mentula PJ, Leppäniemi AK. Nonoperative management ofperforated diverticulitis with extraluminal air is safe and effective in selectedpatients. Dis Colon Rectum. 2014;57:875–81.

72. Rossi GL, Mentz R, Bertone S, Ojea Quintana G, Bilbao S, Im VM, et al.Laparoscopic peritoneal lavage for Hinchey III diverticulitis: is it as effectiveas it is applicable? Dis Colon Rectum. 2014;57:1384–90.

73. Swank HA, Mulder IM, Hoofwijk AG, Nienhuijs SW, Lange JF, Bemelman WA.Dutch diverticular disease collaborative study G. early experience withlaparoscopic lavage for perforated diverticulitis. Br J Surg. 2013;100:704–10.

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 16 of 18

74. Angenete E, Thornell A, Burcharth J, Pommergaard HC, Skullman S, BisgaardT, et al. Laparoscopic lavage is feasible and safe for the treatment ofperforated diverticulitis with purulent peritonitis: the first results from therandomized controlled trial DILALA. Ann Surg. 2016;263:117–22.

75. Schultz JK, Yaqub S, Wallon C, Blecic L, Forsmo HM, Folkesson J, et al.Laparoscopic lavage vs primary resection for acute perforated diverticulitis:the SCANDIV randomized clinical trial. JAMA. 2015;314:1364–75.

76. Vennix S, Musters GD, Mulder IM, Swank HA, Consten EC, Belgers EH, et al.Laparoscopic peritoneal lavage or sigmoidectomy for perforateddiverticulitis with purulent peritonitis: a multicentre, parallel-group,randomised, open-label trial. Lancet. 2015;386(10000):1269–77.

77. Ceresoli M, Coccolini F, Montori G, Catena F, Sartelli M, Ansaloni L.Laparoscopic lavage versus resection in perforated diverticulitis withpurulent peritonitis: a meta-analysis of randomized controlled trials. World JEmerg Surg. 2016;11:42.

78. Penna M, Markar SR, Mackenzie H, Hompes R, Cunningham C. Laparoscopiclavage versus primary resection for acute perforated diverticulitis: reviewand meta-analysis. Ann Surg. 2018;267:252–8.

79. Galbraith N, Carter JV, Netz U, Yang D, Fry DE, McCafferty M, et al.Laparoscopic lavage in the management of perforated diverticulitis: acontemporary meta-analysis. J Gastrointest Surg. 2017;21:1491–9.

80. Cirocchi R, Di Saverio S, Weber DG, Taboła R, Abraha I, Randolph J, et al.Laparoscopic lavage versus surgical resection for acute diverticulitis withgeneralised peritonitis: a systematic review and meta-analysis. TechColoproctol. 2017;21:93–110.

81. Angenete E, Bock D, Rosenberg J, Haglind E. Laparoscopic lavage is superiorto colon resection for perforated purulent diverticulitis—a meta-analysis. IntJ Color Dis. 2017;32:163–9.

82. Shaikh FM, Stewart PM, Walsh SR, Davies RJ. Laparoscopic peritoneal lavageor surgical resection for acute perforated sigmoid diverticulitis: a systematicreview and meta-analysis. Int J Surg. 2017;38:130–7.

83. Biffl WL, Moore FA, Moore EE. The evolving role of laparoscopic lavage anddrainage. J Trauma Acute Care Surg. 2019;86:376.

84. McCafferty MH, Roth L, Jorden J. Current management of diverticulitis. AmSurg. 2008;74:1041–9.

85. Fleming FJ, Gillen P. Reversal of Hartmann's procedure following acutediverticulitis: is timing everything? Int J Color Dis. 2009;24:1219–25.

86. Hong MK, Tomlin AM, Hayes IP, Skandarajah AR. Operative interventionrates for acute diverticulitis: a multicentre state-wide study. ANZ J Surg.2015;85:734–8.

87. Li D, Baxter NN, McLeod RS, Moineddin R, Wilton AS, Nathens AB. Evolvingpractice patterns in the management of acute colonic diverticulitis: apopulation-based analysis. Dis Colon Rectum. 2014;57:1397–405.

88. Chandra V, Nelson H, Larson DR, Harrington JR. Impact of primary resectionon the outcome of patients with perforated diverticulitis. Arch Surg. 2004;139:1221–4.

89. Salem L, Flum DR. Primary anastomosis or Hartmann’s procedure forpatients with diverticular peritonitis? A systematic review. Dis Colon Rectum.2004;47:1953–64.

90. Abbas S. Resection and primary anastomosis in acute complicateddiverticulitis, a systematic review of the literature. Int J Color Dis. 2007;22:351–7.

91. Cirocchi R, Trastulli S, Desiderio J, Listorti C, Boselli C, Parisi A, et al.Treatment of Hinchey stage III-IV diverticulitis: a systematic review andmeta-analysis. Int J Color Dis. 2013;28:447–57.

92. Lee JM, Bai P, Chang J, El Hechi M, Kongkaewpaisan N, Bonde A, et al.Hartmann’s procedure vs primary anastomosis with diverting loopileostomy for acute diverticulitis: nationwide analysis of 2,729 emergencysurgery patients. J Am Coll Surg. 2019;229:48–55.

93. Constantinides VA, Heriot A, Remzi F, Darzi A, Senapati A, Fazio VW, et al.Operative strategies for diverticular peritonitis: a decision analysis betweenprimary resection and anastomosis versus Hartmann’s procedures. AnnSurg. 2007;245:94–103.

94. Oberkofler CE, Rickenbacher A, Raptis DA, Lehmann K, Villiger P, Buchli C,et al. A multicenter randomized clinical trial of primary anastomosis orHartmann’s procedure for perforated left colonic diverticulitis with purulentor fecal peritonitis. Ann Surg. 2012;256:819–26.

95. Bridoux V, Regimbeau JM, Ouaissi M, Mathonnet M, Mauvais F, Houivet E,et al. Hartmann’s procedure or primary anastomosis for generalizedperitonitis due to perforated diverticulitis: a prospective multicenterrandomized trial (DIVERTI). J Am Coll Surg. 2017;225:798–805.

96. Lambrichts DPV, Vennix S, Musters GD, Mulder IM, Swank HA, HoofwijkAGM, et al. Hartmann’s procedure versus sigmoidectomy with primaryanastomosis for perforated diverticulitis with purulent or faecal peritonitis(LADIES): a multicentre, parallel-group, randomised, open-label, superioritytrial. Lancet Gastroenterol Hepatol. 2019;4:599–610.

97. Halim H, Askari A, Nunn R, Hollingshead J. Primary resection anastomosisversus Hartmann’s procedure in Hinchey III and IV diverticulitis. World JEmerg Surg. 2019;14:32.

98. Vennix S, Boersema GS, Buskens CJ, Menon AG, Tanis PJ, Lange JF, et al.Emergency laparoscopic sigmoidectomy for perforated diverticulitis withgeneralised peritonitis: a systematic review. Dig Surg. 2016;33:1–7.

99. Weber DG, Bendinelli C, Balogh ZJ. Damage control surgery for abdominalemergencies. Br J Surg. 2014;101:e109–18.

100. Tartaglia D, Costa G, Camillò A, Castriconi M, Andreano M, Lanza M, et al.Damage control surgery for perforated diverticulitis with diffuse peritonitis:saves lives and reduces ostomy. World J Emerg Surg. 2019;14:19.

101. Kafka-Ritsch R, Birkfellner F, Perathoner A, Raab H, Nehoda H, Pratschke J,et al. Damage control surgery with abdominal vacuum and delayed bowelreconstruction in patients with perforated diverticulitis Hinchey III/IV. JGastrointest Surg. 2012;16:1915–22.

102. Perathoner A, Klaus A, Mühlmann G, Oberwalder M, Margreiter R, Kafka-Ritsch R. Damage control with abdominal vacuum therapy (VAC) tomanage perforated diverticulitis with advanced generalized peritonitis-aproof of concept. Int J Color Dis. 2010;25:767–74.

103. Ordóñez CA, Sánchez AI, Pineda JA, Badiel M, Mesa R, Cardona U, et al.Deferred primary anastomosis versus diversion in patients with severesecondary peritonitis managed with staged laparotomies. World J Surg.2010;34:169–76.

104. Sohn M, Agha A, Heitland W, Gundling F, Steiner P, Iesalnieks I. Damagecontrol strategy for the treatment of perforated diverticulitis withgeneralized peritonitis. Tech Coloproctol. 2016;20:577–83.

105. Sartelli M, Catena F, Abu-Zidan FM, Ansaloni L, Biffl WL, Boermeester MA,et al. Management of intra-abdominal infections: recommendations by theWSES 2016 consensus conference. World J Emerg Surg. 2017;12:22.

106. Kirkpatrick AW, Coccolini F, Ansaloni L, Roberts DJ, Tolonen M, McKee JL,et al. Closed or open after laparotomy (COOL) after source control forsevere complicated intra-abdominal sepsis investigators. Closed or openafter source control laparotomy for severe complicated intra-abdominalsepsis (the COOL trial): study protocol for a randomized controlled trial.World J Emerg Surg. 2018;13:26.

107. Rafferty J, Shellito P, Hyman NH, Buie WD. Standards Committee of theAmerican Society of colon and Rectal surgeons. Practice parameters forsigmoid diverticulitis. Dis Colon Rectum. 2006;49:939–44.

108. Hall JF, Roberts PL, Ricciardi R, Read T, Scheirey C, Wald C, et al. Long-termfollow-up after an initial episode of diverticulitis: what are the predictors ofrecurrence? Dis Colon Rectum. 2011;54:283–8.

109. Humes DJ, West J. Role of acute diverticulitis in the development ofcomplicated colonic diverticular disease and 1-year mortality after diagnosisin the UK: population-based cohort. Gut. 2012;61:95–100.

110. Salem TA, Molloy RG, O’Dwyer PJ. Prospective, five-year follow up study ofpatients with symptomatic uncomplicated diverticular disease. Dis ColonRectum. 2007;50:1–5.

111. El-Sayed C, Radley S, Mytton J, Evison F, Ward ST. Risk of recurrent diseaseand surgery following an admission for acute diverticulitis. Dis ColonRectum. 2018;61:382–9.

112. Regenbogen SE, Hardiman KM, Hendren S, Morris AM. Surgery for diverticulitisin the 21st century: a systematic review. JAMA Surg. 2014;149:292–303.

113. van de Wall BJM, Stam MAW, Draaisma WA, Stellato R, Bemelman WA,Boermeester MA, et al. Surgery versus conservative management forrecurrent and ongoing left-sided diverticulitis (DIRECT trial): an open-label,multicentre, randomised controlled trial. Lancet Gastroenterol Hepatol. 2017;2:13–22.

114. Klarenbeek BR, Samuels M, van der Wal MA, van der Peet DL, Meijerink WJ,Cuesta MA. Indications for elective sigmoid resection in diverticular disease.Ann Surg. 2010;251:670–4.

115. Sawyer RG, Claridge JA, Nathens AB, Rotstein OD, Duane TM, Evans HL,et al. Trial of short-course antimicrobial therapy for intraabdominal infection.NEJM. 2015;372:1996–2005.

116. Chiu TC, Chou YH, Tiu CM, Chiou HJ, Wang HK, Lai YC, et al. Right-sidedcolonic diverticulitis: clinical features, sonographic appearances, andmanagement. J Med Ultrasound. 2017;25:33–9.

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 17 of 18

117. Radhi JM, Ramsay JA, Boutross-Tadross O. Diverticular disease of the rightcolon. BMC Res Notes. 2011;4:1–5.

118. Ha GW, Lee MR, Kim JH. Efficacy of conservative management in patientswith right colonic diverticulitis. ANZ J Surg. 2017;87:467–70.

119. Little A, Culver A. Right-sided sigmoid diverticular perforation. West J EmergMed. 2012;13:103–5.

120. Espinosa J, Sharma R, Lucerna A, Stranges D. Medical approach to rightcolon diverticulitis with perforation. Case Rep Emerg Med. 2017;2017:2563218.

121. Kim SH, Byun CG, Cha JW, Choi SH, Kho YT, Seo DY. Comparative study ofthe clinical features and treatment for right and left colonic diverticulitis. JKorean Soc Coloproctol. 2010;26:407–12.

122. al-Hilaly MA, Razzaq HA, el-Salfiti JI, Abu-Zidan FM, al-Manee MS.Solitarycaecal diverticulitis. Recognition and management. Acta Chir Scand.1989;155:475-8.

123. Kim JY, Park SG, Kang HJ, Lim YA, Pak KH, Yoo T, et al. Prospectiverandomized clinical trial of uncomplicated right-sided colonic diverticulitis:antibiotics versus no antibiotics. Int J Colorectal Dis. 2019;34:1413–20.

124. Destek S, Gül VO. Effectiveness of conservative approach in right colondiverticulitis. Ulus Travma Acil Cerrahi Derg. 2019;25:396–402.

125. Chung BH, Ha GW, Lee MR, Kim JH. Management of colonic diverticulitistailored to location and severity: comparison of the right and the left colon.Ann Coloproctol. 2016;32:228–33.

126. Hildebrand P, Birth M, Bruch HP, Schwandner O. Surgical therapy in right-sided diverticulitis. Zentralbl Chir. 2005;130:123–7.

Publisher’s NoteSpringer Nature remains neutral with regard to jurisdictional claims inpublished maps and institutional affiliations.

Sartelli et al. World Journal of Emergency Surgery (2020) 15:32 Page 18 of 18